Reverberation chambers, also known as mode stirred chambers, have been viewed with increasing interest in electromagnetic (EM) related engineering research. Certain commonly-used electronic devices, such as cell phones, laptops or portable media players, as a few examples, may be immersed in a multipath environment in actual use and may, for example, experience faulty performance as a result of interference from various electromagnetic fields. A reverberation chamber may artificially generate a random or pseudo-random EM field distribution inside of a chamber to mimic an actual multipath environment that electronic equipment may encounter. Reverberation chambers are therefore becoming desirable for electromagnetic compatibility (EMC) measurements or electromagnetic immunity (EMI) assessments.
Currently, transverse electromagnetic (TEM) transmission-line cell devices are used for establishing a standard EM field in a shielded environment. TEM cells have raised more and more research interests in electromagnetic related engineering. Some daily use electronic devices, such as cell-phones, laptops and portable media players are immersed in an electromagnetic interfering environment in real life. The reverberation chamber, which can generate uniform field distribution that mimics planar incident EM wave's in the real world, is increasingly critical to electromagnetic compatibility (EMC) measurements or electromagnetic immunity (EMI) assessments nowadays.
In the conventional TEM cell, the electric filed in the transverse section obeys a static field distribution, which can be calculated by solving the Laplace equation with voltages on the center conductor and ground as the boundary condition. When the electronic device is put in the TEM cell for EMC/EMI testing, EM waves with fixed polarization are directed to the device under test (DUT). Nevertheless, the overall EMC/EMI property of the DUT cannot be evaluated entirely in a test with a fixed polarization. One has to change the orientations of the DUT and repeat the measurement several times to fully characterize the DUT's EMC/EMI property.
Therefore, what is needed is a TEM cell which is able to generate a uniform field inside the cell that emulates the EM waves impinging on the commonly used electronic equipment in the real world. Furthermore, what is needed is a compact device that does not require orientation changes of the DUT in order to achieve a complete measurement of the EMC/EMI properties.